(Adds analyst comment)
BEIJING, Aug 14 (Reuters) - China's aluminium output fell 8.2 percent in July from a record high a month earlier, data showed on Monday, as capacity cuts that have sent prices to multi-year highs start to take their toll on the country's output.
The world's top aluminium producer churned out 2.69 million tonnes of the metal last month, from 2.93 million tonnes in June, according to the National Bureau of Statistics (NBS).
July's output was down 0.3 percent year-on-year, it said.
Overall non-ferrous output was at 4.55 mln tonnes in July, flat year-on-year but down 6.2 percent from 4.85 mln tonnes in June, the bureau said.
The decrease in China's aluminium output follows significant supply-side reform in the sector that sent Shanghai aluminium futures prices to around five-year highs last week.
The eastern province of Shandong, China's biggest aluminium-producing region, ordered a bigger-than-expected 3.2 million tonnes of "illegal" capacity to be closed by the end of July.
The July data points to a considerable slowdown in China's aluminium output, but analysts were sceptical about the accuracy of the bureau's numbers.
"Of course the recent tighter supply-side measures will affect the production number, but maybe not so quickly or so much," said CLSA analyst Daniel Meng, adding that the NBS aluminium data was not very representative of the entire industry.
The NBS figures showed aluminium output is still up 7.5 percent in the first seven months of 2017.
Having determined that China is subsidising its aluminium companies, the U.S. Department of Commerce last week made a preliminary decision to slap antidumping duties ranging from 16.56 percent to 80.97 percent on imports of aluninium foil from China.
Export data released last week showed China's aluminium shipments overseas were down 4.3 percent month-on-month at 440,000 tonnes in July, although they were up 12.8 percent on a year earlier.. (Reporting by Tom Daly; Editing by Richard Pullin)